The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent the work is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
A Redundant Array of Independent Disks (RAID) is a data storage system that stores data on an array of disks and that protects the data from disk failures using different techniques. Depending on the techniques used, a RAID can provide different levels of protection. The levels are identified as RAID0, . . . , RAID5, and so on. In RAID0, data is striped across multiple disks, but no parity or mirroring is used. Consequently, data is lost if a disk fails. In RAID5, data is striped across all the disks, and parity is distributed and stored across all the disks. Consequently, if a disk fails, data stored on the failed disk can be rebuilt from the data and the parity stored on the disks that are functioning normally. While RAID5 uses single parity to protect against single disk failures, RAID6 uses dual parity to protect against two disk failures.